ru;xsaar-e yaar kii jo khulii jalvah-gustarii
zulf-e siyaah bhii shab-e mah-taab ho ga))ii
1) when the {glory/appearance}-spreading of the beloved's cheek became revealed/'opened'
2) even/also the black curls became a moonlit night
khulnaa : 'To open, come open or undone; to open, expand ... to stand out well or conspicuously, to appear to advantage'. (Platts p.879)
gustaarii : 'Spreading, scattering, strewing; diffusing; dispensing, &c. (used as last member of compounds)'. (Platts p.910)
mah-taab : 'The moon; — moonlight, moonshine'. (Platts p.1098)
That is, through the radiance of the glory of the cheeks, something like light spread over the darkness of the curls.
When the glory of the friend/beloved's cheeks spread, then the black curls became half-lit-up, like a moonlit night.
SETS
CURLS: {14,6}
JALVAH: {7,4}
For more on Ghalib's unpublished verses, see the discussion in {4,8x}. See also the overview index.
In the ghazal world the peerless brightness, radiance, glory of the beloved's face is axiomatic. Equally axiomatic is the thickness, the unruliness, the dense blackness of her curls. So really, in this verse the proverbial 'irresistible force meets the immovable object'. The result is a delightfully elegant compromise, a compliment to both face and curls. What else could the result be, but a moonlit night?
Asi:
The glory-scattering that came from the beloved's cheeks-- that is, when the light spread out from her cheeks, even/also her black curls began to appear as a moonlit night.
== Asi, p. 282